An optical electrical device such as light-emitting diode (LED) of the solid-state lighting elements have the characteristics of low heat generation, long operational life and the light emitted by the LEDs has a stable wavelength range so the LEDs have been widely used in various applications. Efforts have been devoted to the luminance of the LED in order to apply the device to the lighting domain and further achieve the goal of energy conservation and carbon reduction.
Many improvements on structures or materials to enhance the light emitting efficiency of an LED have been realized. One of those improvements is to add an enhanced film to increase light extraction, optic-electrical transition efficiency, contact resistance, forward voltage, or the like. However, the high temperature during manufacturing damages the electrical and/or light properties of the enhanced film, and induces the resistances of the enhanced films increasing and the wavelength of maximum transmittance shifting.